1. Field of the Invention
This invention relates to improvements in transmitters and receivers, and more particularly to apparatus for enabling the duplex or simultaneous operation of a transmitter and a receiver on the same or closly adjacent frequencies.
2. Description of the Prior Art
In the past, it has been often desired to operate a transmitter and receiver on the same or closly adjacent frequencies; for instance, in some cases it is advantageous to operate the transmitter on an upper sideband and the receiver on a lower sideband of the same frequency. To date, however, this has been ineffectively achieved.
Also, in the past, in order to achieve isolation between transmitters and receivers, complicated and expensive filtering arrangements have been required to be incorporated, oftentimes, into the hardware of the respective transmitters and receivers.